Heater cut-out for electric lamps.



No. 721,602. I PATENTED FEB. 24, 1903.

H. N. POTTER.' HEATER GUT-OUT FOR ELECTRIC LAMPS.

APPLICATION FILED A11 6. 9, 18919. RENEWED APR. 30, 1901.

NO MODEL.

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HENRY NOEL POTTER, OF GOTTINGEN, GERMANY, ASSIGNOR TO GEORGEWESTINGHOUSE, OF PITTSBURG, PENNSYLVANIA.

HEATER CUT-OUT FOR ELECTRIC LAMPS.

SPECIFICATION forming part of Letters Patent N 0. 721,602, datedFebruary 24, 1903. Application filed August 9, 1899. Renewed April 30,1901. Serial No. 58,198. (No model.)

To all whom it may concern:

Be it known that I, HENRY NOEL POTTER, a citizen of the United States ofAmerica, and a resident of Gottingen, Germany, haveinvented certain newand useful Improvements in Heater Out-Outs for Electric Lamps, of whichthe following is a specification.

The invention relates to the class of device employed for cutting out ofcircuit the elec- IO tric heating device employed for heating theglowers of electric lamps to conducting temperature; and the object ofthe invention is to provide a simple and efficient device forautomatically effecting this result.

I 5 In another application I have described a special form of ballast orsteadying resistance to be employed in series with the glower of thisform of lamp. This ballast device consists of a strip or wire of ironinclosed in an atmosphere of inert gas-such, for instance,

as hydrogenand my present invention relates particularly to theutilization of this form of ballast device for operating an automaticcut-out for the heater cireuit; but certain features of the inventionhave a wider application.

The ballast-wire usually consists of a comparatively short length ofiron wire; but the length varies according to the purposes orcharacteristics of the lamp with which it is to be employed say from aninch to ten or twelve inches,according to the circumstances. This Wirewhen current is traversing the glower is heated to a red or dull-redtemperature and when so heated expands somewhat in length. I make use ofthis expansion to operate a circuit-breaker through which the circuit tothe heater is closed when the glower is not in operation. Variousdifferent forms of circuit-breakers thus operated may be employed.

In Figure 1 of the drawings I have illustrated one form, and in Fig. 2 amodification, ot' the invention.

5 Referring to'the drawings, G represents the glower of a lamp of thecharacter referred to, composed of the rare earths suitably prepared andformed into a proper shape. The glower is a non-conductor of electricitywhen cold and a conductor when heated to the proper temperature.

The preliminary heat is given to the glower by means of an electricheating device-such, for instance, as that shown at A in the drawings.The heater, here shown diagrammatically, comprises a length ofconductor, usually of platinu m,arranged in proximity to the glower anddesigned to be raised to a high temperature by the passage of anelectric current. The heat necessary for rendering the glower conductiveis imparted 6o thereto from the glower; but when the heater has beenrendered conductive it is desirable that the heater be cut out of thecircuit, so that energy will no longer be wasted in continuing tooperate the heater. Moreover, continuous operation of the heater wouldsoon destroy it.

In series with the glower is connected the balancing orcurrent-restraining deviceB,

-consisting of a strip of iron, usually in the form of wire, as shown atb, which is sealed in a tube b, formed of glass or other suitablematerial. The ends of the iron wire are usually connected to shortplatinum leading-in wires 0, by means of which connections are made tothe work-circuit. The wire I) is stretched tightly between the twoleading-in wires or between insulated supports d, carried within thetube. A contact-arm e and a contact-point e therefor are also containedwithin the tube. When the Wire Z) is cold and occupies a straight linebetween its supports, the arm 6 is in contact with its point c. When,however, the iron wire is expanded by heat by the passage of currenttherethrough, the arm 6 moves automatically away from its contact-point.This maybe accomplished by a spring or equivalent device f, tending todraw the arm away from the point. This tendency, however, is opposed bycon- 0 nection g from the iron Wire to the arm 0. This connection ismade by either anon-conducting material or a piece of wire having aninsulated point within its length, so that the current will not traverseit. When thelamp 5 is not in use, the arm 6 is drawn against the point eby reason of the connection g; but when the iron wire has been expandedthe springfwithdraws the arm from the point, and thus interrupts thecircuit connections there- Ioc through. One end of the arm 6 isconnected with the terminal of the balancing-wire b lated at thenecessary points.

either within or outside of the tube. A conductor 3 connects thisterminal with one side 1 of the main circuit. The contact-point e isconnected by conductor 4 with one termi nal of the heating-conductor A,and the other terminal of the heating-conductor is connected by aconductor 5 with the other side 2 of the main circuit.

The balancing-conductor and the circuitbreaker are both included in theinclosing tube 19, a suitable leading-in wire b leading through the wallof the tube to the contactpoint e. The tube is filled with an inertatmospheresuch, for instance, as hydrogen the pressure of which may bevaried according to circumstances. Usually I employ a pressure aboutequal to atmospheric pressure. By reason of this inert atmosphere thecontact-points will not be oxidized or deteriorated, and therefore theymay be of other material than platinum. Inclosing the contacts alsoserves to keep them free from dust and dirt and mechanical injury.

In Fig. 2 I have illustrated a modification of the device in which themotion is transmitted to the arm 6 through a lever 6 carriedlby a frame6 of non-conducting material or of suitable conducting material insu-The lever c is pivoted to the frame 6 and connected at one end to theiron wire I), and at its other end it carries rigidly the end of the arm6 which is remote from the contact-point e. A small spring it normallytends to draw the arm away from its contact-point; but it is heldagainst that point so long as no current is traversing the wire I) bythe tension of that wire. When, however, the wire Z) is expanded byheat, the spring 70 moves the arm 6 away from its contact-point e, andthus breaks the circuit.

I make no claim, broadly, herein to the utilization of the energyexpended in the ballast-conductor for the purpose of breaking theheater-circuit, but have made such broad invention the subject-matter ofanother application, filed the 2d day of September, 1899, Serial No.729,277.

I claim as my invention 1. The combination of an electric lamp glowerwhich is a non-conductor when cold and a conductor when heated, anelectric heater therefor, a balancing device included in series with theglower, a cut-out for the heater consisting of two contact-pointsnormally in contact with each other, means tending to separate suchpoints and a mechanical connection with one of said points forseparating the points upon the expansion of the said balancing device.

2. The combination with a lamp-glower composed of material which is anon-conductor when cold and a conductor when hot and a balancing-00nductor in series therewith, consisting of an iron wire inclosed within anair-tight case containing an inert atmosphere, a circuit-controller alsocontained within such case and mechanically operated by the expansion ofthe said iron wire and a heater for said glower having its circuitconnections through said circuit-controller.

3. The combination of an air-tight inclosing globe, an iron ballastdevice for electric lamps inclosed therein, and a circuit maker andbreaker also inclosed therein and having a mechanical connection withsaid ballast device whereby the expansion and contraction of the ballastdevice operate said circuit maker and breaker.

4. The combination of an electric lamp glower, a ballast-wire of softiron in series therewith, a heater-circuit in shunt around the glowerand the ballast-wire and a circuit making and breaking device for theheatercircuit mechanically operated by the expansion and contraction ofthe ballast-wire, substantially as described.

5. A combined steadying and circuit-controlling device for electriclamps consisting of a ballast-wire, a frame for supporting the same,contact-points carried by said frame and connections from saidballast-wire to one of the contacts of said circuit-controlling devicefor operating the latter by the expansion and contraction of theballast-wire.

HENRY NOEL POTTER.

